Summary of Work: We are carrying out a large six-year population-based case-control study of facial clefts in Norway, incorporating molecular genetic tools and in-depth questionnaires to examine the separate and combined roles of genetics and environment. The incidence of facial clefts in Norway is one of the highest in the world. We plan to enroll 600 babies with facial clefts and 1100 random live births from the general population. Cases are enrolled within two months of birth. Blood samples are collected from the cases and their biological parents, and cheek swabs are collected from the controls and their parents. In preparation for the analysis of these data, we have developed new statistical methods for detecting gene effects within families of affected persons that have distinct advantages over previous approaches. This method can be useful for the study of diseases besides birth defects. - facial cleft, cleft lip, cleft palate, gene-environment interaction - Human Subjects